Some times for some reason with some customers modems and their software it will not work properly with PARITY setting of NONE (NULL). Try changing the PARITY setting to TRUE (EVEN). This should resolve the issue, however our system does support all formats. It seems to be a localized issue with some users computer based software and modems.
The settings should be the following:
Country: United Kingdom
Dial-in number: 09018600011 (from international +448726149997)
Modem Settings: 7,e,1
Modem Speed: All
This issue is not applicable and does not occur with standard security alarm control panels!